Liquid circulation system and liquid modification system

Abstract

To provide a liquid circulation device and a liquid modification device which resist losing a function of removing a foreign matter, even if a function of generating fine bubbles is stopped.SOLUTION: A liquid circulation device includes: a delivery pump 11 for pressure-sending a coolant liquid CL from a coolant tank 4 storing the coolant liquid CL; a main flow channel 13 which is connected to the discharge port of the delivery pump 11, and circulates the coolant liquid CL discharged from the delivery pump 11 in the coolant tank 4; a filter 15 connected to the main flow channel 13; a bypass flow channel 18 which is branched from the main flow channel 13 at a first position on the downstream of the filter 15, and is returned to the main flow channel 13 at a second position on the downstream of the first position; and a fine bubble generation pump device 20 which is connected to the bypass flow channel 18, and makes fine bubbles contained in the coolant liquid CL flowing in the bypass flow channel 18.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a liquid circulation device and a liquid reforming device.

Background Art

[0002] Patent Document 1 discloses an ultrafine bubble generator that contains ultrafine bubbles (UFB) in a coolant.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a liquid circulation device (liquid reforming device) that contains fine bubbles in an aqueous liquid and removes foreign substances mixed in the aqueous liquid, the portion that generates fine bubbles may be blocked due to clogging of foreign substances or the like. In this case, all functions in the liquid circulation device may stop.

[0005] An object of the present disclosure is to provide a liquid circulation device and a liquid reforming device in which the function of removing foreign substances is less likely to be lost even when the function of generating fine bubbles is stopped.

Means for Solving the Problems

[0006] One example of a liquid circulation system includes a discharge pump (11) that pumps aqueous liquid (CL) from a tank (4) in which aqueous liquid (CL) is stored, a main channel (13) connected to the discharge port of the discharge pump (11) and circulating the aqueous liquid (CL) discharged from the discharge pump (11) back to the tank (4), a filter (15) connected to the main channel (13), a bypass channel (18) that branches off from the main channel (13) at a first position downstream of the filter (15) and returns to the main channel (13) at a second position downstream of the first position, and a microbubble generating pump device (20) connected to the bypass channel (18) and causing the aqueous liquid (CL) flowing through the bypass channel (18) to contain microbubbles.

[0007] Furthermore, one example of a liquid modification apparatus includes a housing (51), a main pipe (13B) that penetrates the inside and outside of the housing (51) such that a supply end (13Ba) to which aqueous liquid (CL) is supplied and a discharge end (13Bb) to which aqueous liquid (CL) is discharged are located outside the housing (51), a filter (15) connected to the main pipe (13B) and located inside the housing (51), a bypass pipe (18) located inside the housing (51) that branches off from the main pipe (13B) at a first position downstream of the filter (15) and returns to the main pipe (13B) at a second position downstream of the first position, and a microbubble generating pump device (20) connected to the bypass pipe (18) and located inside the housing (51) and configured to contain microbubbles in the aqueous liquid (CL) flowing through the bypass pipe (18).

[0008] In the liquid circulation device (10) and liquid modification device (50) described above, the aqueous liquid (CL) stored in the tank (4) is sent to the main pipe (13B) by the discharge pump (11). The aqueous liquid (CL) passes through the filter (15) and then returns to the tank (4). A portion of the aqueous liquid (CL) passes through the bypass pipe (18). Since the bypass pipe (18) is equipped with a bubble generation pump device (20), the aqueous liquid (CL) passing through the bypass pipe (18) returns to the main pipe (13B) containing fine bubbles. Thus, because the microbubble generation pump device (20) is provided in the bypass pipe (18), even if the microbubble generation pump device (20) becomes clogged with foreign matter, the aqueous liquid can still be circulated by passing it through the main pipe (13B), and the foreign matter can be removed by the filter (15).

[0009] In one example, the inner diameter of the bypass channel (18) may be smaller than the inner diameter of the main channel (13). In this configuration, the amount of aqueous liquid (CL) necessary for the operation of the microbubble generating pump device (20) can be appropriately guided from the aqueous liquid (CL) flowing through the main channel (13) to the bypass channel (18).

[0010] The liquid circulation device further includes a flow meter (19) that detects the flow rate of the main flow path (13) at a position downstream of the filter (15) and upstream of the first position, and the delivery pump (11) and the microbubble generation pump device (20) may stop operating when the flow rate detected by the flow meter (19) is less than or equal to a predetermined value. In this configuration, loads on the delivery pump (11) and the microbubble generation pump device (20) are suppressed.

[0011] The microbubble generating pump device (20) may include a high-pressure pump (22) that pumps the aqueous liquid (CL) flowing through the bypass channel (18) at a discharge pressure higher than that of the delivery pump (11), and a microbubble generator (25) connected downstream of the discharge port of the high-pressure pump (22) to incorporate microbubbles into the flowing aqueous liquid (CL). By sending the aqueous liquid (CL) to the microbubble generator (25) by the high-pressure pump (22), microbubbles can be generated appropriately.

[0012] The liquid circulation device further includes a pressure sensor (29) for detecting the discharge pressure of the high-pressure pump (22), and the delivery pump (11) and the microbubble generation pump device (20) may stop operating when the discharge pressure of the high-pressure pump (22) detected by the pressure sensor (29) is below a predetermined value. In this configuration, loads on the delivery pump (11) and the microbubble generation pump device (20) are suppressed.

[0013] The housing (51) has a rectangular parallelepiped shape and includes a first side wall (55) and a first door (57) facing each other, and a second side wall (56) and a second door (58) facing each other. The microbubble generating pump device (20) is provided with a pressure regulating handle (27a) for adjusting the discharge pressure of the aqueous liquid (CL). The filter (15) is positioned closer to the first door (57) than to the first side wall (55) in a plan view. The microbubble generating pump device (20) may be positioned closer to the first side wall (55) than to the first door (57) in a plan view, such that the pressure regulating handle (27a) is closer to the second door (58) than to the second side wall (56). In this configuration, the pressure regulating handle (27a) can be adjusted with the second door (58) open. In addition, maintenance of the filter (15) (e.g., cartridge replacement) can be performed with the first door (57) open. Since the filter (15) is close to the first door (57) and the pressure regulating handle (27a) is far from the first door (57), it is possible to prevent accidentally touching the pressure regulating handle (27a) and changing the discharge pressure when maintaining the filter (15). [Effects of the Invention]

[0014] According to this disclosure, a liquid circulation device and a liquid modification device are provided in which the function of removing foreign matter is less likely to be lost even if the function of generating microbubbles is stopped. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram illustrating an example of a liquid circulation system. [Figure 2] This is a block diagram showing the control system of an example liquid circulation system. [Figure 3] This is a perspective view showing a liquid reforming device used in an example of a liquid circulation system. [Figure 4] This is a perspective view showing an example of a liquid reforming apparatus. [Figure 5] This is a perspective view showing an example of a liquid reforming apparatus. [Figure 6] This is a schematic diagram showing a control panel for an example of a liquid circulation system. [Modes for carrying out the invention]

[0016] The liquid circulation system of this disclosure will be described below with reference to the drawings. In the description of the drawings, the same reference numerals will be used for identical or equivalent elements, and redundant descriptions will be omitted. In the description, the Cartesian coordinate system defined by the X, Y, and Z axes shown in the drawings may be referred to.

[0017] FIG. 1 is a schematic diagram showing a liquid circulation system according to an example. FIG. 2 is a block diagram showing a control system of the liquid circulation system. FIGS. 3 to 5 are perspective views showing a liquid reforming device used in the liquid circulation system. FIG. 6 is a schematic diagram showing a control panel of the liquid circulation system. FIG. 3 shows a state where the door of the liquid reforming device is closed, FIG. 4 shows a state where the door is open, and in FIG. 5, the door, side wall, upper wall, and control panel are omitted. The liquid circulation system 1 shown in an example includes a liquid circulation device 10 that circulates a coolant liquid CL, which is an aqueous liquid stored in a coolant tank 4. Note that the liquid circulation device 10 may include a coolant liquid circulation unit (not shown) for supplying the coolant liquid CL stored in the coolant tank 4 to a machine tool (not shown), collecting the coolant liquid CL used in the machine tool, and returning it to the coolant tank 4. Note that the aqueous liquid may be a liquid mainly composed of water.

[0018] The liquid circulation device 10 includes a delivery pump 11, a main flow path 13, and a liquid reforming device 50. An example delivery pump 11 is disposed in a tank in which an aqueous liquid to be circulated is stored, and pumps the aqueous liquid. In this example, the delivery pump 11 is disposed inside the coolant tank 4 in which the coolant liquid CL is stored. The delivery pump 11 has a suction port and a discharge port, and discharges the coolant liquid CL supplied from the suction port from the discharge port. The delivery pump 11 may be a submersible pump configured by a so-called centrifugal pump or the like.

[0019] The main flow path 13 is connected to the discharge port of the delivery pump 11, and circulates the coolant liquid CL discharged from the delivery pump  11 to the coolant tank 4. As shown in FIG. 1, an example main flow path 13 includes a main pipe 13A connecting the delivery pump 11 and the liquid reforming device 50, a main pipe 13B provided in the liquid reforming device 50, and a main pipe 13C provided between the liquid reforming device 50 and the coolant tank 4. For example, the main flow path 13 may be configured by a flexible tube. Note that in FIG. 1, the direction of the flow of the coolant liquid CL flowing through the pipe is indicated by an arrow. In the following description, the terms “upstream” and “downstream” are based on the direction of the flow of the coolant liquid CL.

[0020] The liquid reforming device 50 generates a fine bubble-containing liquid by incorporating fine bubbles into a coolant liquid CL which is an aqueous liquid. The fine bubble-containing liquid is an aqueous liquid containing minute bubbles. In one example, the fine bubble-containing liquid is a coolant liquid containing ultrafine bubbles (UFB) with a diameter of about several tens of nm to 1 μm. Hereinafter, the coolant liquid containing ultrafine bubbles may be particularly referred to as a UFB coolant liquid.

[0021] One example of the liquid reforming device 50 includes a housing 51, a main pipe 13B, a filter 15, a bypass flow path 18, a fine bubble generation pump device 20, and a control panel 40. As shown in FIGS. 3 to 5, the housing 51 has a frame 52 assembled to exhibit a substantially rectangular parallelepiped shape, and an upper wall 53, a first side wall 55, a second side wall 56, a first door 57, and a second door 58 attached to the frame 52. Further, four casters 59 for moving the liquid reforming device 50 are provided at the lower part of the frame 52. The upper wall 53 is disposed at the upper part of the frame 52 and exhibits a rectangular plate shape so as to cover the upper part of the frame 52. The first side wall 55 and the first door 57 face each other. The second side wall 56 and the second door 58 face each other. The first side wall 55 and the second side wall 56 are fixed to the frame 52 by fastening members such as screws. The first door 57 and the second door 58 are supported by support members 57a, 58a such as hinges so as to be openable and closable with respect to the frame 52. In the illustrated example, the first door 57 and the second door 58 are respectively supported by hinges on a pair of diagonal struts 52a, 52b among the struts constituting the frame 52.

[0022] The main pipe 13B has a supply end (inlet end) 13Ba to which the coolant liquid CL pumped to the delivery pump 11 is supplied, and a discharge end 13Bb to which the coolant liquid CL is discharged. The main pipe 13B penetrates the inside and outside of the housing 51 such that the supply end 13Ba and the discharge end 13Bb are located outside the housing 51. The supply end 13Ba is connected to the end of the main pipe 13A opposite to the end connected to the delivery pump 11. The discharge end 13Bb is connected to the end of the main pipe 13C opposite to the end facing the coolant tank 4.

[0023] The filter 15 is located inside the housing 51 and connected to the main piping 13B. The filter 15 is configured to filter out foreign matter such as sludge (metal shavings) mixed in the coolant liquid CL. One example of the filter 15 may consist of a bottomed cylindrical cartridge housing and a replaceable cartridge filter housed inside the cartridge housing. For example, as the coolant liquid CL flowing through the main piping 13B passes inside the cartridge housing, foreign matter corresponding to the mesh size of the cartridge filter is removed. Multiple filters 15 may be provided.

[0024] In the illustrated example, the filter 15 consists of a first filter 15A and a second filter 15B located downstream of the first filter 15A. The mesh size of the second filter 15B is set to be smaller than that of the first filter 15A. The coolant liquid CL supplied from the supply end 13Ba of the main pipe 13B first passes through the first filter 15A in the housing 51 to remove larger foreign matter, and immediately afterwards passes through the second filter 15B to remove smaller foreign matter. In a plan view, the filter 15 is positioned closer to the first door 57 than to the first side wall 55. For example, the first filter 15A and the second filter 15B are arranged side by side along the X direction and are positioned facing the opening of the first door 57.

[0025] The bypass channel 18 is arranged within the housing 51 to branch off from the main pipe 13B at a first position downstream of the filter 15, and to return to the main pipe 13B at a second position downstream of the first position. The inner diameter of the bypass channel 18 may be smaller than the inner diameter of the main channel 13. For example, if the inner diameter of the bypass channel 18 is a and the inner diameter of the main channel 13 is b, then a / b may be about 1 / 4 to 2 / 3. As an example, if the inner diameter (diameter) of the main channel 13 is about 15 mm, the inner diameter of the bypass channel 18 may be about 10 mm. For example, the bypass channel 18 may be made of a flexible tube.

[0026] In one example, a three-way joint 17A is positioned at a first location downstream of the location where the filter 15 is installed on the main pipe 13B. Two of the three-way joint 17A's connection ports are connected to the main pipe 13B, and the remaining connection port is connected to the bypass pipe 18A. As a result, the coolant liquid CL flowing through the main pipe 13B branches into two paths: one that continues to flow through the main pipe 13B, and another that separates from the main pipe 13B and flows through the bypass pipe 18A. Further downstream from the first location, a third three-way joint 17B is positioned at a second location. Two of the three-way joint 17B's connection ports are connected to the main pipe 13B, and the remaining connection port is connected to the bypass pipe 18B. As a result, the coolant liquid CL flowing through the main pipe 13B merges with the coolant liquid CL flowing through the bypass pipe 18B at the three-way joint 17B, and then flows through the main pipe 13B downstream.

[0027] The three-way joints 17A and 17B may be equipped with valves to regulate the flow of liquid between the main channel 13 and the bypass channel 18. In the illustrated example, a flow meter 19 for detecting the flow rate of the main channel 13 is located downstream of the filter 15 and upstream of the first position.

[0028] The microbubble generation pump device 20 is connected to bypass pipes 18A and 18B within the housing 51. In a plan view, the microbubble generation pump device 20 is positioned closer to the first side wall 55 than to the first door 57. For example, in the Y direction, the area where the microbubble generation pump device 20 is located and the area where the filter 15 is located do not overlap. The microbubble generation pump device 20 is configured to contain UFB in the coolant liquid CL flowing through the bypass pipe 18A. One example of the microbubble generation pump device 20 includes a high-pressure pump 22 and a microbubble generator 25. The high-pressure pump 22 discharges aqueous liquid supplied from the supply port from the discharge port. One example of the high-pressure pump 22 is a pump that pumps the coolant liquid CL at a discharge pressure higher than the discharge pressure of the delivery pump 11, and may be configured as, for example, a so-called Polanja pump. For example, the discharge pressure of the supply pump 11 may be approximately 0.3 MPa or less, and the discharge pressure of the high-pressure pump 22 may be approximately 5.0 MPa or less.

[0029] The microbubble generator 25 is connected downstream of the discharge port of the high-pressure pump 22. The microbubble generator 25 has an inlet and an outlet, and the aqueous liquid flowing in from the inlet contains UFB and is discharged from the outlet. Various existing methods can be used for generating UFB in the microbubble generator 25. The inlet of the microbubble generator 25 may be connected to the discharge port of the high-pressure pump 22. The outlet of the microbubble generator 25 may be connected to the bypass pipe 18B. That is, the coolant liquid CL that flows from the main pipe 13B through the bypass pipe 18A to the microbubble generation pump device 20 becomes UFB coolant liquid by flowing through the high-pressure pump 22 and the microbubble generator 25, and rejoins the main pipe 13B via the bypass pipe 18B.

[0030] In the illustrated example, a pressure regulating valve 27 is provided at the discharge port of the high-pressure pump 22, and the inlet of the microbubble generator 25 is connected to the discharge port of the pressure regulating valve 27 via a pressure sensor 29. The pressure regulating valve 27 adjusts the pressure (discharge volume) of the coolant liquid CL discharged from the high-pressure pump 22. In the illustrated example, the pressure regulating valve 27 is adjusted by rotating a rotary pressure regulating handle 27a. The microbubble generation pump device 20 is positioned in the lower part of the housing 51 such that the pressure regulating handle 27a is oriented closer to the second door 58 than to the second side wall 56. The pressure regulating valve 27 is provided with a discharge port for discharging excess coolant liquid CL that was not discharged due to pressure adjustment. The discharge port is connected to an excess water pipe 16 that is connected to the main pipe 13B downstream of the connection point with the bypass pipe 18B. That is, the excess water is discharged into the main pipe 13B. The pressure sensor 29 detects the discharge pressure of the coolant liquid CL discharged from the pressure regulating valve 27.

[0031] Furthermore, the liquid modification device 50 may have a leak sensor 31 (see Figure 1) for detecting water leakage from the microbubble generation pump device 20. For example, in the lower part of the housing 51, a water leakage receiving pan 33 is provided below the microbubble generation pump device 20, at a position closer to the second door 58 than to the second side wall 56. The water leakage sensor 31 may be provided inside the water leakage receiving pan 33. Note that in the lower part of the housing 51, the area where the water leakage receiving pan 33 is not located (i.e., the area closer to the second side wall 56) does not have a bottom plate or the like, and is composed only of the frame 52.

[0032] The control panel (control device) 40 controls the operation of the liquid circulation device 10. In one example, the control panel 40 may be electrically and communicatively connected to the delivery pump 11, high-pressure pump 22, flow meter 19, pressure sensor 29, and leak sensor 31. The control panel 40 has a control unit 41 and a power switch 42, alarm lamp 43, alarm buzzer 45, reset button 46, hour meter 47, daily timer 48, etc., connected to the control unit 41 (see Figure 6). For example, the second door 58 is provided with a transparent window 58b made of acrylic or the like, so that the user can see the control panel 40 from outside the housing 51 through the window 58b.

[0033] The power switch 42 is a switch that controls the power supply to the entire liquid circulation device 10. The alarm lamp 43 is a lamp that notifies when a predetermined abnormality has been detected in the liquid circulation system. The alarm buzzer 45 is a buzzer that notifies when a predetermined abnormality has been detected in the liquid circulation device 10. The reset button 46 is a button that stops the operation of the alarm lamp 43 and the alarm buzzer 45 when they have been activated. The hour meter 47 is a device that records and displays the operating status of the liquid circulation device 10. For example, the hour meter 47 may record and display the cumulative operating time of the liquid circulation device 10. The hour meter 47 may also record and display the history of abnormalities that have occurred in the liquid circulation device 10. The daily timer 48 is a device for reserving the operating time of the liquid circulation device 10. For example, the user can set in advance the time period during the day when they want the liquid circulation device 10 to operate using the daily timer 48.

[0034] The control unit 41 is configured as an electronic control unit that includes, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input / output circuits, etc. The control unit 41 controls the operation of the liquid circulation device 10 by having the processor execute a program stored in the memory device. One example of a control unit 41 has an operation control unit 41a, an abnormality detection unit 41b, and a state management unit 41c as functional units.

[0035] The operation control unit 41a is a functional unit for controlling the operation of the liquid circulation device 10, and controls the operation of the discharge pump 11 and the high-pressure pump 22. For example, the operation control unit 41a operates the discharge pump 11 and the high-pressure pump 22 when the signal input from the daily timer 48 indicates an operating state. In addition, the operation control unit 41a stops the operation of the discharge pump 11 and the high-pressure pump 22 when an abnormality is detected in the liquid circulation device 10 by the abnormality detection unit 41b. The operation control unit 41a may also notify the status management unit 41c of the operating status of the discharge pump 11 and the high-pressure pump 22.

[0036] The abnormality detection unit 41b is a functional unit that detects abnormalities in the liquid circulation device 10. When it detects an abnormality, it notifies the operation control unit 41a and the state management unit 41c of the abnormality and activates the alarm lamp 43 and alarm buzzer 45. For example, the abnormality detection unit 41b detects that an abnormality in flow rate reduction has occurred when the flow rate measured by the flow meter 19 is below a predetermined threshold. The abnormality detection unit 41b also detects that an abnormality has occurred in the discharge pressure of the high-pressure pump 22 when the pressure measured by the pressure sensor 29 is below a predetermined threshold. Furthermore, the abnormality detection unit 41b detects water leakage from the microbubble generation pump device 20 based on the signal input from the water leakage sensor 31.

[0037] The status management unit 41c is a functional unit that manages the operating status of the liquid circulation device 10 and outputs the operating status of the liquid circulation device 10 to the hour meter 47. For example, the status management unit 41c may determine whether the liquid circulation device 10 is operating or stopped based on the operating status of the discharge pump 11 and the high-pressure pump 22 input from the operation control unit 41a, and output the determination result to the hour meter 47. In this case, the hour meter 47 may record the cumulative operating time of the liquid circulation device 10 based on the input determination result. The status management unit 41c may also output data to the hour meter 47 indicating the date and time when a flow rate reduction abnormality occurred, data indicating the date and time when an abnormality occurred in the discharge pressure of the high-pressure pump 22, and data indicating the date and time when a water leak occurred, based on abnormality detection information input from the abnormality detection unit 41b. In this case, the hour meter 47 can record data on the date and time when various abnormalities occurred.

[0038] In the liquid circulation device 10, when the signal input from the daily timer 48 indicates an operating state, the operation control unit 41a operates the delivery pump 11 and the high-pressure pump 22. The operation of the delivery pump 11 causes the coolant liquid CL stored in the coolant tank 4 to be pumped through the main pipe 13A. The pumped coolant liquid CL flows into the main pipe 13B of the liquid reforming device 50, where it passes through the first filter 15A and the second filter 15B, removing foreign matter such as sludge. The coolant liquid CL that has passed through the filters 15 is branched at a three-way joint 17A located at the first position. That is, a portion of the coolant liquid CL flows into the bypass pipe 18A. The coolant liquid CL that flows into the bypass pipe 18A is reformed into UFB coolant liquid by passing through the microbubble generation pump device 20, and then flows into the bypass pipe 18B. The UFB coolant flowing through the bypass pipe 18B merges with the coolant CL flowing through the main pipe 13B at the three-way joint 17B. The merged coolant then flows into the main pipe 13C and returns to the coolant tank 4.

[0039] As described above, a liquid circulation device 10 that can be used in one example of a liquid circulation system 1 includes a discharge pump 11 that pumps coolant liquid CL from a coolant tank 4 in which coolant liquid CL is stored, a main flow path 13 connected to the discharge port of the discharge pump 11 and circulating the coolant liquid CL discharged from the discharge pump 11 back to the coolant tank 4, a filter 15 connected to the main flow path 13, a bypass flow path 18 that branches off from the main flow path 13 at a first position downstream of the filter 15 and returns to the main flow path 13 at a second position downstream of the first position, and a microbubble generating pump device 20 connected to the bypass flow path 18 and containing microbubbles in the coolant liquid CL flowing through the bypass flow path 18.

[0040] Furthermore, an example of a liquid reforming device 50 that constitutes the liquid circulation device 10 includes a housing 51, a main pipe 13B that penetrates the inside and outside of the housing 51 such that a supply end 13Ba to which coolant liquid CL is supplied and a discharge end 13Bb to which coolant liquid CL is discharged are located outside the housing 51, a filter 15 connected to the main pipe 13B and located inside the housing 51, a bypass channel 18 located inside the housing 51 that branches off from the main pipe 13B at a first position downstream of the filter 15 and returns to the main pipe 13B at a second position downstream of the first position, and a microbubble generating pump device 20 located inside the housing 51 that is connected to the bypass channel 18 and configured to contain microbubbles in the coolant liquid CL flowing through the bypass channel 18.

[0041] In the liquid circulation device 10 described above, the coolant liquid CL stored in the coolant tank 4 is sent to the main flow path 13 by the discharge pump 11. After passing through the filter 15, the coolant liquid CL returns to the coolant tank 4. A portion of the coolant liquid CL passes through the bypass flow path 18. Since the bypass flow path 18 is equipped with a microbubble generating pump device 20, the coolant liquid CL passing through the bypass flow path 18 returns to the main flow path 13 containing microbubbles. By incorporating microbubbles into the coolant liquid CL, bacterial growth in the coolant liquid CL can be suppressed even without additives. This allows for a longer lifespan of the coolant liquid.

[0042] Furthermore, if the microbubble generation pump device 20 is directly connected to the main flow path 13 without going through the bypass flow path 18, it is possible that the microbubble generation pump device 20 may not operate properly due to the difference in discharge pressure and suction pressure between the delivery pump 11 and the high-pressure pump 22. In this disclosure, by connecting the microbubble generation pump device 20 to the bypass flow path 18, an appropriate amount of coolant liquid CL is supplied to the microbubble generation pump device 20. Also, if the microbubble generation pump device 20 is connected to the main flow path 13, even if the microbubble generation pump device 20 operates properly, the amount of circulating coolant liquid CL depends on the processing capacity of the microbubble generation pump device 20, which may reduce the processing capacity of the liquid circulation.

[0043] Since the microbubble generation pump device 20 is located in the bypass channel 18, even if the microbubble generation pump device 20 becomes clogged with foreign matter, the coolant liquid CL can still circulate by passing through the main channel 13, and the foreign matter can be removed by the filter 15. Furthermore, even when the microbubble generation pump device 20 is stopped for maintenance or other reasons, the coolant liquid CL can still be circulated by passing through the main channel 13. In addition, the liquid circulation device 10 can circulate an amount of coolant liquid CL that exceeds the discharge rate of the microbubble generation pump device 20.

[0044] In one example, the inner diameter of the bypass channel 18 may be smaller than the inner diameter of the main channel 13. In this configuration, the required amount of coolant CL for the microbubble generation pump device 20 can be appropriately guided from the coolant CL flowing through the main channel 13 to the bypass channel 18.

[0045] The liquid circulation device 10 includes a flow meter 19 that detects the flow rate of the main flow path 13 at a position downstream of the filter 15 and upstream of the first position. The discharge pump 11 and the microbubble generation pump device 20 may stop operating when the flow rate detected by the flow meter 19 is below a predetermined value. This configuration helps to prevent unnecessary loads on the discharge pump 11 and the microbubble generation pump device 20.

[0046] The microbubble generating pump device 20 may include a high-pressure pump 22 that pumps the coolant liquid CL flowing through the bypass channel 18 at a discharge pressure higher than the discharge pressure of the delivery pump 11, and a microbubble generator 25 connected downstream of the discharge port of the high-pressure pump 22 to incorporate microbubbles into the flowing coolant liquid CL. By sending the coolant liquid CL to the microbubble generator 25 by the high-pressure pump 22, microbubbles can be generated appropriately.

[0047] The liquid circulation device 10 is equipped with a pressure sensor 29 that detects the discharge pressure of the high-pressure pump 22, and the delivery pump 11 and the microbubble generation pump device 20 may stop operating when the discharge pressure of the high-pressure pump 22 detected by the pressure sensor 29 is below a predetermined value. In this configuration, unnecessary loads on the delivery pump 11 and the microbubble generation pump device 20 are suppressed. After the delivery pump 11 and the microbubble generation pump device 20 have stopped, the delivery pump 11 may be operated while maintenance of the microbubble generation pump device 20 is performed.

[0048] The housing 51 has a rectangular parallelepiped shape and includes a first side wall 55 and a first door 57 facing each other, and a second side wall 56 and a second door 58 facing each other. The microbubble generation pump device 20 is provided with a pressure regulating handle 27a for adjusting the discharge pressure of the coolant liquid CL. The filter 15 is positioned closer to the first door 57 than to the first side wall 55 in a plan view, and the microbubble generation pump device 20 may be positioned closer to the first side wall 55 than to the first door 57, with the pressure regulating handle 27a positioned closer to the second door 58 than to the second side wall 56 in a plan view. In this configuration, the pressure regulating handle 27a can be adjusted with the second door 58 open. In addition, maintenance of the filter 15, such as cartridge replacement, can be performed with the first door 57 open. Since the filter 15 is close to the first door 57 and the pressure regulating handle 27a is far from the first door 57, it is possible to prevent accidentally touching the pressure regulating handle 27a and changing the discharge pressure when maintaining the filter 15.

[0049] Although embodiments of the present invention have been described above, the liquid circulation device is not limited to the embodiments described above.

[0050] For example, we have described a configuration in which the discharge pump is located inside the coolant tank, but for example, the intake piping connected to the suction port of the discharge pump may also be located inside the coolant tank.

[0051] Liquid modifiers can be used in applications other than liquid circulation systems that circulate coolant. For example, a liquid modifier may be used in liquid circulation systems that circulate other liquids, such as water circulation systems for ponds, fountains, or hydroponics. Furthermore, a liquid modifier may be used in liquid circulation systems that circulate other liquids, such as water sprayers that spray water from a water tank.

[0052] Embodiments illustrated in this disclosure may be described as follows: [1] A discharge pump (11) that pumps the aqueous liquid (CL) from a tank (4) where the aqueous liquid (CL) is stored, A main flow path (13) is connected to the discharge port of the discharge pump (11) and circulates the aqueous liquid (CL) discharged from the discharge pump (11) to the tank (4), A filter (15) connected to the main flow path (13), A bypass channel (18) branches off from the main channel (13) at a first position downstream of the filter (15) and returns to the main channel (13) at a second position downstream of the first position, A liquid circulation device comprising a microbubble generating pump device (20) connected to the bypass channel (18) and which causes the aqueous liquid (CL) flowing through the bypass channel (18) to contain microbubbles. [2] The liquid circulation device according to [1], wherein the inner diameter of the bypass channel (18) is smaller than the inner diameter of the main channel (13). [3] The system further includes a flow meter (19) for detecting the flow rate of the main channel (13) at a location downstream of the filter (15) and upstream of the first location, The liquid circulation apparatus according to [1] or [2], wherein the discharge pump (11) and the microbubble generating pump device (20) stop operating when the flow rate detected by the flow meter (19) is less than or equal to a predetermined value. [4] The aforementioned microbubble generating pump device (20) A high-pressure pump (22) pumps the aqueous liquid (CL) flowing through the bypass channel (18) at a discharge pressure higher than the discharge pressure of the delivery pump (11), A liquid circulation device according to any one of [1] to [3], comprising a microbubble generator (25) connected downstream of the discharge port of the high-pressure pump (22) and causing the flowing aqueous liquid (CL) to contain the microbubbles. [5] The system further includes a pressure sensor (29) for detecting the discharge pressure of the high-pressure pump (22), The liquid circulation apparatus according to [4], wherein the discharge pump (11) and the microbubble generating pump device (20) stop operating when the discharge pressure of the high-pressure pump (22), detected by the pressure sensor (29), is less than or equal to a predetermined value. [6] The aqueous liquid (CL) is a coolant liquid. The liquid circulation device according to any one of [1] to [5], wherein the tank (4) is a coolant tank (4) in which the coolant liquid is stored. [7] A liquid modification apparatus that dispenses a supplied aqueous liquid (CL) containing fine bubbles, The casing (51) and A main pipe (13B) that penetrates the inside and outside of the housing (51) is provided such that the supply end (13Ba) to which the aqueous liquid (CL) is supplied and the discharge end (13Bb) to which the aqueous liquid (CL) is discharged are located outside the housing (51), A filter (15) is connected to the main piping (13B) and is located inside the housing (51), A bypass pipe (18) is arranged within the housing (51) such that it branches off from the main pipe (13B) at a first position downstream of the filter (15) and returns to the main pipe (13B) at a second position downstream of the first position, A liquid modification apparatus comprising: a microbubble generating pump device (20) connected to the bypass pipe (18) and configured to incorporate microbubbles into the aqueous liquid (CL) flowing through the bypass pipe (18), and located within the housing (51). [8] The housing (51) has a rectangular parallelepiped shape and includes a first side wall (55) and a first door (57) facing each other, and a second side wall (56) and a second door (58) facing each other. The microbubble generating pump device (20) is provided with a pressure regulating handle (27a) for adjusting the discharge pressure of the aqueous liquid (CL). The filter (15) is positioned in a plan view closer to the first door (57) than to the first side wall (55). The liquid reforming apparatus according to [7], wherein the microbubble generating pump device (20) is positioned such that, in a plan view, the pressure regulating handle (27a) is closer to the second door (58) than the second side wall (56), and closer to the first side wall (55) than the first door (57). [Explanation of Symbols]

[0053] 1...Liquid circulation system, 4...Coolant tank, 10...Liquid circulation device, 11...Discharge pump, 13...Main flow path, 15...Filter, 18...Bypass flow path, 20...Microbubble generation pump device, 50...Liquid modification device, CL...Coolant liquid.

Claims

1. A discharge pump (11) that pumps the aqueous liquid (CL) from a tank (4) where the aqueous liquid (CL) is stored, A main flow path (13) is connected to the discharge port of the discharge pump (11) and circulates the aqueous liquid (CL) discharged from the discharge pump (11) to the tank (4), A filter (15) connected to the main flow path (13), A bypass channel (18) branches off from the main channel (13) at a first position downstream of the filter (15) and returns to the main channel (13) at a second position downstream of the first position, A liquid circulation device comprising a microbubble generating pump device (20) connected to the bypass channel (18), which pumps the aqueous liquid (CL) flowing through the bypass channel (18) and incorporates microbubbles into the aqueous liquid (CL).

2. The liquid circulation device according to claim 1, wherein the inner diameter of the bypass channel (18) is smaller than the inner diameter of the main channel (13).

3. The system further includes a flow meter (19) for detecting the flow rate of the main channel (13) at a location downstream of the filter (15) and upstream of the first location, The liquid circulation device according to claim 1, wherein the discharge pump (11) and the microbubble generating pump device (20) stop operating when the flow rate detected by the flow meter (19) is less than or equal to a predetermined value.

4. The aforementioned microbubble generation pump device (20) A high-pressure pump (22) pumps the aqueous liquid (CL) flowing through the bypass channel (18) at a discharge pressure higher than the discharge pressure of the delivery pump (11), The liquid circulation apparatus according to claim 1, further comprising a microbubble generator (25) connected downstream of the discharge port of the high-pressure pump (22) and for incorporating the microbubbles into the circulating aqueous liquid (CL).

5. The system further includes a pressure sensor (29) for detecting the discharge pressure of the high-pressure pump (22), The liquid circulation device according to claim 4, wherein the delivery pump (11) and the microbubble generating pump device (20) stop operating when the discharge pressure of the high-pressure pump (22), detected by the pressure sensor (29), is less than or equal to a predetermined value.

6. The aqueous liquid (CL) is a coolant liquid. The liquid circulation device according to any one of claims 1 to 5, wherein the tank (4) is a coolant tank (4) in which the coolant liquid is stored.

7. A liquid modification apparatus that dispenses a supplied aqueous liquid (CL) containing fine bubbles, The casing (51) and A main pipe (13B) that penetrates the inside and outside of the housing (51) is provided such that the supply end (13Ba) to which the aqueous liquid (CL) is supplied and the discharge end (13Bb) to which the aqueous liquid (CL) is discharged are located outside the housing (51), A filter (15) is connected to the main piping (13B) and is located inside the housing (51), A bypass pipe (18) is arranged within the housing (51) such that it branches off from the main pipe (13B) at a first position downstream of the filter (15) and returns to the main pipe (13B) at a second position downstream of the first position, A liquid modification apparatus comprising: a microbubble generating pump device (20) connected to the bypass pipe (18) and configured to incorporate microbubbles into the aqueous liquid (CL) flowing through the bypass pipe (18), and located within the housing (51).

8. The housing (51) has a rectangular parallelepiped shape and includes a first side wall (55) and a first door (57) facing each other, and a second side wall (56) and a second door (58) facing each other. The microbubble generating pump device (20) is provided with a pressure regulating handle (27a) for adjusting the discharge pressure of the aqueous liquid (CL). The filter (15) is positioned in a plan view closer to the first door (57) than to the first side wall (55). The liquid reforming apparatus according to claim 7, wherein the microbubble generating pump device (20) is positioned such that, in a plan view, the pressure regulating handle (27a) is closer to the second door (58) than the second side wall (56), and closer to the first side wall (55) than the first door (57).

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